NOVITATES ZOOLOGICAE XXIII. 1916. 351 



Group A. — Frons with subprisniatical truncate process. Abdomen very 

 densely spinulose on upperside. Forefemnr slender, without apical 

 tooth, subconvex on underside. R 1 of forewing (vein 6) from above 

 angle of discocellnlars. Tenth tergite (<$) clavate, with the apex 

 truncate-sinuate. 



Group B. — Frons with an irregular wart or scars only visible if the hair 

 is removed. Spinules on upperside of abdomen less dense than in 

 Group A. Forefemnr stout, flattened beneath, without apical tooth. 

 R 1 of forewing from below angle of discocellnlars. Apex of tenth 

 tergite (S) pointed. 



Group C. — Frons with raised lines or scars visible only if the hair is 

 removed. Spinules of abdomen as in Group B. Forefemur stout, 

 flattened beneath, with a tooth on innerside at apex. R 1 of forewing 

 from angle of discocellulars. Apex of tenth tergite (c?) pointed. 



After having studied Powell's work on the larvae and OberthüVs figures of 

 imagines, I am convinced that my Groups A, B, and C of imagines coincide with 

 Powell's Groups A, B, and C of larvae. This being so, there is no reasonable 

 doubt that all the species described by Oberthür and others belong to one or the 

 other of the three groups of imagines. 



The task of placing the species and varieties hitherto published into their 

 respective groups is most difficult for me. The descriptions are of little or no 

 help, — and the figures ? In many instances the artist, or the camera, has repro- 

 duced the characteristic distinctions in ueuration, of which the authors themselves 

 were unaware ; but as that is not universally the case, much is left to guessing. 

 The types of nearly all the doubtful forms are in French collections. It should, 

 therefore, uot be difficult for a French entomologist with some knowledge of 

 morphology to place the specimens correctly. 



The first-described species, aegrota and infuscata Klug (1832), are not doubtful 

 to me. The position of R l in the forewing (vein 6) is indicated in the original 

 figures. Enlarged drawings of the forewings,* which I owe to the kindness of the 

 Director of the Berlin Museum, show that vein in the same positions (Plate VIII., 

 figs. 16 and 17). According to the figures aegrota belongs to Group A, and infuscata 

 to Group B. 



S. codeti Aust. (1880) is represented in the Tring Museum by the name-type 

 and numerous other specimens. It belongs to Group A. 



S. arcanaria Milliere (1884) was described as a Geometrid, the description 

 being accompanied by a very unsatisfactory figure. The original specimens (one <3 

 in coll. Staudinger at Dresden, two <$ S in coll. Milliere in the Royal Museum at 

 Sofia) are not accessible to me at present. If I may venture a guess, I refer the 

 species to Group A. The specimens figured as arcanaria by Oberthür, Lep. Comp. v. 

 pi. C (1911), apparently belong to the same group. 



In 1908 Oberthür described two new species in Bull. Soc. Ent. & ranee, p. 48 : 



S. powelii and S. chretieni. The former, which is figured in Lep. Comp. iii. 

 pi. 21 (1909), gives me the impression of belonging to Group A. The figure of the 

 second species, chretieni, appears in Lip. Comp. iv. pi. 36. Although vein R 1 of 



* Although these drawings are meant to be " rough sketches " only, they are so instructive that I 

 consider them superior to any of the published drawings, and I therefore do not hesitate in using them 

 for illustrating the present paper. 



